Gene Editing Center Q&A with Dr. Pelletier

Stephane Pelletier, Ph.D., recently established the IU Gene Editing Center, an institutionally subsidized shared facility whose mission is to provide investigators access to genome editing technologies.

Pelletier

The new center replaces the Transgenic & Knock-out Mouse core, which was led by IU Distinguished Professor Loren Field, Ph.D.

Pelletier, associate professor of clinical medical and molecular genetics, joined IU School of Medicine in the summer of 2020. He holds a bachelor’s degree in biochemistry and a master’s degree in pharmacology from the University of Sherbrooke and a doctorate in pharmacology from the University of Montreal. He pioneered the implementation of CRISPR technology for mouse genome engineering at St. Jude Children’s Research Hospital in 2013 and supervised the generation of hundreds of mouse models and cell lines, establishing himself as a leader in the field.

He answered questions about the new IU Gene Editing Center.

Q: First off, is this just a name change of the shared facility from Transgenic & Knock-out Mouse Core to IU Gene Editing Center? Or is it a totally different shared facility?

A: The IUGEC is a new shared facility that offers three main categories of services: 1.) Model generation services, 2.) traditional transgenic and knock out services, and 3.) technology development services.

For the generation of mouse models and cell lines with user-defined mutation(s), the center takes care of every aspect of the process, from the design of the genetic modification to the generation of the model. The center will continue to offer services offered by the former Transgenic and Knock Out Core run by Dr. Loren Field. These services include zygote injections, in vitro fertilization, and embryo, egg, and sperm cryopreservation. The center can also work with investigators to secure funding for more complex projects like genome-wide screens or for the development and/or implementation of new genome editing technologies.

Q: If you had a chance to tell each cancer center researcher about this shared facility, what would you tell them about it?

A: I would tell them that we care about their research and that we will do everything in our power to provide them with the best services they can get. This is a facility run by researchers for researchers.

Q: What services do you think cancer center researchers would be most interested in?

A: I believe cancer center researchers will be most interested in our model generation services. These services can be used to generate mouse models and cell lines with user-defined mutations, which can be used to test the oncogenic potential of mutations identified in cancer patients, validate potential therapeutic targets, or be used as preclinical models for the development of therapeutics. Eventually, our model generation services could also be used to engineer CAR T-cells, allogeneic CAR T-cells, or immune cells that hunt down cancer cells more efficiently.

Q: You’re considered a leader in CRISPR technology. How would you describe CRISPR?

A: CRISPR is an extraordinarily powerful technology that holds great promises for the treatment of various diseases and has several applications in biotechnology. CRISPR is short for Clustered Regularly Interspaced Palindromic Repeats and CRISPR-associated protein 9 (Cas9). Cas9, when complexed with two small RNA molecules, functions as an endonuclease that cleaves double stranded DNA molecules. Cleavage of double stranded DNA in cells (chromosomes) triggers DNA repair mechanisms and these can be tricked to introduce changes one would want. CRISPR-Cas9 cleavage specificity is provided by one of the small RNA molecules, the CRISPR-RNA (crRNA), which recognizes a 20-nucleotide long DNA sequence via Watson-Crick base pairing. Thus, programming or re-programming of CRISPR-Cas9 to target another site within a genome can be done by simply changing this 20-nucleotide long sequence in the crRNA. This is a lot easier than completely re-engineering zinc finger nucleases or TALE nucleases to target another genomic sequence.  

Q: Does the shared facility offer CRISPR?

A: The center uses various CRISPR-based systems for the generation of animal models and cell lines. The center also provides plasmids encoding CRISPR-Cas9 to users if they want to engineer models themselves. These include a series of conventional or retroviral-based plasmids with various drug selection markers or fluorescent markers.

Q: How is CRISPR changing cancer research?

A: CRISPR is changing cancer research in many ways. The technology is used to engineer animal models and cell lines that can be used as preclinical models for drug development, validate potential therapeutic targets, and gain insights into disease mechanisms. The technology also accelerates the development of chimeric antigen receptor (CAR) T-cells, allogeneic CAR T-cells, exhaustion-resistant CAR- T-cells, or immune cells that better recognize cancer cells and hunt them down.